<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <title>Java io流（三） | 凌歆的博客</title>
    <meta name="generator" content="VuePress 1.9.5">
    <link rel="icon" href="/img/favicon.ico">
    <meta name="description" content="web前端技术博客,专注web前端学习与总结。JavaScript,js,ES6,TypeScript,vue,React,python,css3,html5,Node,git,github等技术文章。">
    <meta name="keywords" content="前端博客,个人技术博客,前端,前端开发,前端框架,web前端,前端面试题,技术文档,学习,面试,JavaScript,js,ES6,TypeScript,vue,python,css3,html5,Node,git,github,markdown">
    <meta name="baidu-site-verification" content="7F55weZDDc">
    <meta name="theme-color" content="#11a8cd">
    
    <link rel="preload" href="/assets/css/0.styles.d9c8cf8c.css" as="style"><link rel="preload" href="/assets/js/app.57550e13.js" as="script"><link rel="preload" href="/assets/js/2.f014c35f.js" as="script"><link rel="preload" href="/assets/js/87.e06ee05e.js" as="script"><link rel="prefetch" href="/assets/js/10.03a98811.js"><link rel="prefetch" href="/assets/js/100.145e708e.js"><link rel="prefetch" href="/assets/js/101.098ca5c8.js"><link rel="prefetch" href="/assets/js/102.4d45c69a.js"><link rel="prefetch" href="/assets/js/103.499de505.js"><link rel="prefetch" href="/assets/js/104.c2c1b9b6.js"><link rel="prefetch" href="/assets/js/105.4e9b0663.js"><link rel="prefetch" href="/assets/js/106.9bb8cf6f.js"><link rel="prefetch" href="/assets/js/107.a81b32d7.js"><link rel="prefetch" href="/assets/js/108.81511e67.js"><link rel="prefetch" href="/assets/js/109.6a6741bf.js"><link rel="prefetch" href="/assets/js/11.e8729182.js"><link rel="prefetch" href="/assets/js/110.de657fe7.js"><link rel="prefetch" href="/assets/js/111.b092af6d.js"><link rel="prefetch" href="/assets/js/112.2dca5709.js"><link rel="prefetch" href="/assets/js/113.dbed1fac.js"><link rel="prefetch" href="/assets/js/114.e95a0131.js"><link rel="prefetch" href="/assets/js/115.2e3e8285.js"><link rel="prefetch" href="/assets/js/116.e64f7fec.js"><link rel="prefetch" href="/assets/js/117.583552c9.js"><link rel="prefetch" href="/assets/js/118.aa5d18f0.js"><link rel="prefetch" href="/assets/js/119.0c7b52d7.js"><link rel="prefetch" href="/assets/js/12.d63acec2.js"><link rel="prefetch" href="/assets/js/120.13f86281.js"><link rel="prefetch" href="/assets/js/121.e2b5b7f9.js"><link rel="prefetch" href="/assets/js/122.5252216a.js"><link rel="prefetch" href="/assets/js/123.8b8a3503.js"><link rel="prefetch" href="/assets/js/124.60df855c.js"><link rel="prefetch" href="/assets/js/125.f073ab1c.js"><link rel="prefetch" href="/assets/js/126.7b73de6a.js"><link rel="prefetch" href="/assets/js/127.4e25971c.js"><link rel="prefetch" href="/assets/js/128.0edf0e06.js"><link rel="prefetch" href="/assets/js/129.5cb5a70a.js"><link rel="prefetch" href="/assets/js/13.2259ef71.js"><link rel="prefetch" href="/assets/js/130.00247fda.js"><link rel="prefetch" href="/assets/js/131.d6fc003a.js"><link rel="prefetch" href="/assets/js/132.1a32b18f.js"><link rel="prefetch" href="/assets/js/133.e46c0193.js"><link rel="prefetch" href="/assets/js/134.a6ad681f.js"><link rel="prefetch" href="/assets/js/135.2fcbe137.js"><link rel="prefetch" href="/assets/js/136.f69bf451.js"><link rel="prefetch" href="/assets/js/137.b9ef2fcc.js"><link rel="prefetch" href="/assets/js/138.7fdd9feb.js"><link rel="prefetch" href="/assets/js/139.a3a37c91.js"><link rel="prefetch" href="/assets/js/14.0d6b23b9.js"><link rel="prefetch" href="/assets/js/140.a7c013ae.js"><link rel="prefetch" href="/assets/js/141.956c36ce.js"><link rel="prefetch" href="/assets/js/142.5aacfe42.js"><link rel="prefetch" href="/assets/js/143.57d691ef.js"><link rel="prefetch" href="/assets/js/144.b1e5766e.js"><link rel="prefetch" href="/assets/js/145.463284b7.js"><link rel="prefetch" href="/assets/js/146.6cc6420c.js"><link rel="prefetch" href="/assets/js/147.5b78c5a2.js"><link rel="prefetch" href="/assets/js/148.8d1d7679.js"><link rel="prefetch" href="/assets/js/149.4e0eb213.js"><link rel="prefetch" href="/assets/js/15.f6fde69d.js"><link rel="prefetch" href="/assets/js/150.b183de37.js"><link rel="prefetch" href="/assets/js/151.729ae770.js"><link rel="prefetch" href="/assets/js/152.b1297018.js"><link rel="prefetch" href="/assets/js/153.bb991bca.js"><link rel="prefetch" href="/assets/js/154.6f2286aa.js"><link rel="prefetch" href="/assets/js/155.6a9c7e4d.js"><link rel="prefetch" href="/assets/js/156.f7bd535d.js"><link rel="prefetch" href="/assets/js/157.64c0065c.js"><link rel="prefetch" href="/assets/js/158.d31ae949.js"><link rel="prefetch" href="/assets/js/159.7daea8a7.js"><link rel="prefetch" href="/assets/js/16.7be21beb.js"><link rel="prefetch" href="/assets/js/160.33cc971a.js"><link rel="prefetch" href="/assets/js/161.1676442a.js"><link rel="prefetch" href="/assets/js/162.71378046.js"><link rel="prefetch" href="/assets/js/163.99e49959.js"><link rel="prefetch" href="/assets/js/164.306f07d2.js"><link rel="prefetch" href="/assets/js/165.170977c7.js"><link rel="prefetch" href="/assets/js/166.f8602525.js"><link rel="prefetch" href="/assets/js/167.eea5c001.js"><link rel="prefetch" href="/assets/js/168.0146a311.js"><link rel="prefetch" href="/assets/js/169.05f9c9d9.js"><link rel="prefetch" href="/assets/js/17.2543f471.js"><link rel="prefetch" href="/assets/js/170.25d602b2.js"><link rel="prefetch" href="/assets/js/171.1ada26a6.js"><link rel="prefetch" href="/assets/js/172.2a0f697c.js"><link rel="prefetch" href="/assets/js/173.230d8ca8.js"><link rel="prefetch" href="/assets/js/174.e3758a2b.js"><link rel="prefetch" href="/assets/js/175.0f19f8ea.js"><link rel="prefetch" href="/assets/js/176.bf70d37d.js"><link rel="prefetch" href="/assets/js/177.4400f272.js"><link rel="prefetch" href="/assets/js/178.85af7b89.js"><link rel="prefetch" href="/assets/js/179.4cfaaaa2.js"><link rel="prefetch" href="/assets/js/18.394415f8.js"><link rel="prefetch" href="/assets/js/180.449c8409.js"><link rel="prefetch" href="/assets/js/181.73276924.js"><link rel="prefetch" href="/assets/js/182.5fab25cc.js"><link rel="prefetch" href="/assets/js/183.ecd4934d.js"><link rel="prefetch" href="/assets/js/184.246092cf.js"><link rel="prefetch" href="/assets/js/185.c671cd86.js"><link rel="prefetch" href="/assets/js/186.49bd1963.js"><link rel="prefetch" href="/assets/js/187.1fb32764.js"><link rel="prefetch" href="/assets/js/188.7c6885e9.js"><link rel="prefetch" href="/assets/js/189.a8701dec.js"><link rel="prefetch" href="/assets/js/19.ca7db8ea.js"><link rel="prefetch" href="/assets/js/190.ae3d3bde.js"><link rel="prefetch" href="/assets/js/191.ad7cd44e.js"><link rel="prefetch" href="/assets/js/192.bc443842.js"><link rel="prefetch" href="/assets/js/193.e4755764.js"><link rel="prefetch" href="/assets/js/194.814112ce.js"><link rel="prefetch" href="/assets/js/195.1c0aaa80.js"><link rel="prefetch" href="/assets/js/196.a6bd7add.js"><link rel="prefetch" href="/assets/js/20.4e91cd31.js"><link rel="prefetch" href="/assets/js/21.f095e6e1.js"><link rel="prefetch" href="/assets/js/22.72f4b8ab.js"><link rel="prefetch" href="/assets/js/23.e94eb9d2.js"><link rel="prefetch" href="/assets/js/24.0eae7d6f.js"><link rel="prefetch" href="/assets/js/25.36157609.js"><link rel="prefetch" href="/assets/js/26.dc5b6cba.js"><link rel="prefetch" href="/assets/js/27.c19b7b63.js"><link rel="prefetch" href="/assets/js/28.3aceae59.js"><link rel="prefetch" href="/assets/js/29.536091b3.js"><link rel="prefetch" href="/assets/js/3.d11119c4.js"><link rel="prefetch" href="/assets/js/30.821a4a30.js"><link rel="prefetch" href="/assets/js/31.5238784c.js"><link rel="prefetch" href="/assets/js/32.10bc7179.js"><link rel="prefetch" href="/assets/js/33.c1ed69c9.js"><link rel="prefetch" href="/assets/js/34.8d384231.js"><link rel="prefetch" href="/assets/js/35.d8890e52.js"><link rel="prefetch" href="/assets/js/36.eca37ad5.js"><link rel="prefetch" href="/assets/js/37.802549e3.js"><link rel="prefetch" href="/assets/js/38.53841770.js"><link rel="prefetch" href="/assets/js/39.7ae44409.js"><link rel="prefetch" href="/assets/js/4.493b9bca.js"><link rel="prefetch" href="/assets/js/40.ce56364a.js"><link rel="prefetch" href="/assets/js/41.85f0114b.js"><link rel="prefetch" href="/assets/js/42.714da6e2.js"><link rel="prefetch" href="/assets/js/43.fee4437c.js"><link rel="prefetch" href="/assets/js/44.b039b68b.js"><link rel="prefetch" href="/assets/js/45.96a55605.js"><link rel="prefetch" href="/assets/js/46.956ffb03.js"><link rel="prefetch" href="/assets/js/47.147d9218.js"><link rel="prefetch" href="/assets/js/48.ff787b40.js"><link rel="prefetch" href="/assets/js/49.871eee87.js"><link rel="prefetch" href="/assets/js/5.e0ba07d7.js"><link rel="prefetch" href="/assets/js/50.99b7c29e.js"><link rel="prefetch" href="/assets/js/51.8ecbf4ba.js"><link rel="prefetch" href="/assets/js/52.53d91d7e.js"><link rel="prefetch" href="/assets/js/53.af8a0d2a.js"><link rel="prefetch" href="/assets/js/54.a2f848b5.js"><link rel="prefetch" href="/assets/js/55.267e9947.js"><link rel="prefetch" href="/assets/js/56.0b201c40.js"><link rel="prefetch" href="/assets/js/57.cbdfd6f7.js"><link rel="prefetch" href="/assets/js/58.636c0c3f.js"><link rel="prefetch" href="/assets/js/59.fc9216c4.js"><link rel="prefetch" href="/assets/js/6.b98373f2.js"><link rel="prefetch" href="/assets/js/60.34f16fc4.js"><link rel="prefetch" href="/assets/js/61.4d130bd8.js"><link rel="prefetch" href="/assets/js/62.927caa10.js"><link rel="prefetch" href="/assets/js/63.a451fee0.js"><link rel="prefetch" href="/assets/js/64.32a5d47b.js"><link rel="prefetch" href="/assets/js/65.bc099429.js"><link rel="prefetch" href="/assets/js/66.3953050d.js"><link rel="prefetch" href="/assets/js/67.e934823b.js"><link rel="prefetch" href="/assets/js/68.4bcb52b0.js"><link rel="prefetch" href="/assets/js/69.bede18c8.js"><link rel="prefetch" href="/assets/js/7.8de8df2d.js"><link rel="prefetch" href="/assets/js/70.fce1daac.js"><link rel="prefetch" href="/assets/js/71.ea0a8c5d.js"><link rel="prefetch" href="/assets/js/72.15382c9e.js"><link rel="prefetch" href="/assets/js/73.848364d3.js"><link rel="prefetch" href="/assets/js/74.5fd08a50.js"><link rel="prefetch" href="/assets/js/75.c937c70d.js"><link rel="prefetch" href="/assets/js/76.a0dacd5a.js"><link rel="prefetch" href="/assets/js/77.4019cc23.js"><link rel="prefetch" href="/assets/js/78.9676a9e1.js"><link rel="prefetch" href="/assets/js/79.e46e10d5.js"><link rel="prefetch" href="/assets/js/8.2098eb96.js"><link rel="prefetch" href="/assets/js/80.987e83cb.js"><link rel="prefetch" href="/assets/js/81.eb98ff36.js"><link rel="prefetch" href="/assets/js/82.623561a7.js"><link rel="prefetch" href="/assets/js/83.e256d909.js"><link rel="prefetch" href="/assets/js/84.7d06a550.js"><link rel="prefetch" href="/assets/js/85.b8d9879e.js"><link rel="prefetch" href="/assets/js/86.31c4581b.js"><link rel="prefetch" href="/assets/js/88.81ef718d.js"><link rel="prefetch" href="/assets/js/89.ba237d2f.js"><link rel="prefetch" href="/assets/js/9.36092fd0.js"><link rel="prefetch" href="/assets/js/90.ad2c9d92.js"><link rel="prefetch" href="/assets/js/91.a661f52d.js"><link rel="prefetch" href="/assets/js/92.1c28035b.js"><link rel="prefetch" href="/assets/js/93.c8b8e3d6.js"><link rel="prefetch" href="/assets/js/94.b6bc4a44.js"><link rel="prefetch" href="/assets/js/95.92cea882.js"><link rel="prefetch" href="/assets/js/96.5373491b.js"><link rel="prefetch" href="/assets/js/97.bb39efc8.js"><link rel="prefetch" href="/assets/js/98.af7a030f.js"><link rel="prefetch" href="/assets/js/99.07dc87d8.js">
    <link rel="stylesheet" href="/assets/css/0.styles.d9c8cf8c.css">
  </head>
  <body class="theme-mode-light">
    <div id="app" data-server-rendered="true"><div class="theme-container sidebar-open have-rightmenu"><header class="navbar blur"><div title="目录" class="sidebar-button"><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" role="img" viewBox="0 0 448 512" class="icon"><path fill="currentColor" d="M436 124H12c-6.627 0-12-5.373-12-12V80c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12z"></path></svg></div> <a href="/" class="home-link router-link-active"><img src="https://lingxin-tanhua.oss-cn-shanghai.aliyuncs.com/QQ%E6%88%AA%E5%9B%BE20220503092755.png" alt="凌歆的博客" class="logo"> <span class="site-name can-hide">凌歆的博客</span></a> <div class="links"><div class="search-box"><input aria-label="Search" autocomplete="off" spellcheck="false" value=""> <!----></div> <nav class="nav-links can-hide"><div class="nav-item"><a href="/" class="nav-link">首页</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="前端" class="dropdown-title"><a href="/web/" class="link-title">前端</a> <span class="title" style="display:none;">前端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><h4>学习笔记</h4> <ul class="dropdown-subitem-wrapper"><li class="dropdown-subitem"><a href="/note/html/" class="nav-link">HTML笔记</a></li><li class="dropdown-subitem"><a href="/note/js-low/" class="nav-link">JavaScript基础笔记</a></li><li class="dropdown-subitem"><a href="/note/js-high/" class="nav-link">JavaScript高阶笔记</a></li><li class="dropdown-subitem"><a href="/note/js-dom-bom/" class="nav-link">JavaScript DOM和BOM笔记</a></li><li class="dropdown-subitem"><a href="/note/jquery/" class="nav-link">jQuery笔记</a></li><li class="dropdown-subitem"><a href="/note/ajax/" class="nav-link">Ajax笔记</a></li><li class="dropdown-subitem"><a href="/note/nodejs/" class="nav-link">NodeJs笔记</a></li><li class="dropdown-subitem"><a href="/note/reg/" class="nav-link">正则表达式笔记</a></li><li class="dropdown-subitem"><a href="/note/vue/" class="nav-link">Vue笔记</a></li><li class="dropdown-subitem"><a href="/note/react/" class="nav-link">react笔记</a></li><li class="dropdown-subitem"><a href="/note/wx/" class="nav-link">微信小程序笔记</a></li><li class="dropdown-subitem"><a href="/note/uniapp/" class="nav-link">uniapp笔记</a></li><li class="dropdown-subitem"><a href="/note/echarts/" class="nav-link">echarts笔记</a></li><li class="dropdown-subitem"><a href="/note/git/" class="nav-link">Git笔记</a></li></ul></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="后端" class="dropdown-title"><a href="/back/" class="link-title">后端</a> <span class="title" style="display:none;">后端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/java/" class="nav-link">JAVA</a></li><li class="dropdown-item"><!----> <a href="/note/javaweb/" class="nav-link">JavaWeb</a></li><li class="dropdown-item"><!----> <a href="/note/mysql/" class="nav-link">MySql</a></li><li class="dropdown-item"><!----> <a href="/note/ssm/" class="nav-link">ssm</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="算法" class="dropdown-title"><a href="/algor/" class="link-title">算法</a> <span class="title" style="display:none;">算法</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/sf/" class="nav-link">算法训练营</a></li><li class="dropdown-item"><!----> <a href="/note/js-sf/" class="nav-link">js数据结构与算法</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="面试" class="dropdown-title"><a href="/mianshi/" class="link-title">面试</a> <span class="title" style="display:none;">面试</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/lqb/" class="nav-link">蓝桥杯备战</a></li><li class="dropdown-item"><!----> <a href="/note/ms/" class="nav-link">前端面试</a></li><li class="dropdown-item"><!----> <a href="/note/hmms/" class="nav-link">黑马面试</a></li><li class="dropdown-item"><!----> <a href="/note/xzms/" class="nav-link">校招零距离面试</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="解决方案" class="dropdown-title"><a href="/resolve/" class="link-title">解决方案</a> <span class="title" style="display:none;">解决方案</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/qd-resolve/" class="nav-link">前端解决方案</a></li><li class="dropdown-item"><!----> <a href="/note/hd-resolve/" class="nav-link">后端解决方案</a></li></ul></div></div><div class="nav-item"><a href="/pages/beb6c0bd8a66cea6/" class="nav-link">收藏</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="索引" class="dropdown-title"><a href="/archives/" class="link-title">索引</a> <span class="title" style="display:none;">索引</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/categories/" class="nav-link">分类</a></li><li class="dropdown-item"><!----> <a href="/tags/" class="nav-link">标签</a></li><li class="dropdown-item"><!----> <a href="/archives/" class="nav-link">归档</a></li></ul></div></div> <a href="https://github.com/linxin1123/vuepress-blog" target="_blank" rel="noopener noreferrer" class="repo-link">
    GitHub
    <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav></div></header> <div class="sidebar-mask"></div> <div class="sidebar-hover-trigger"></div> <aside class="sidebar" style="display:none;"><div class="blogger"><img src="https://lingxin-tanhua.oss-cn-shanghai.aliyuncs.com/QQ%E6%88%AA%E5%9B%BE20220503092755.png"> <div class="blogger-info"><h3>lingxin</h3> <span>凌歆</span></div></div> <nav class="nav-links"><div class="nav-item"><a href="/" class="nav-link">首页</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="前端" class="dropdown-title"><a href="/web/" class="link-title">前端</a> <span class="title" style="display:none;">前端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><h4>学习笔记</h4> <ul class="dropdown-subitem-wrapper"><li class="dropdown-subitem"><a href="/note/html/" class="nav-link">HTML笔记</a></li><li class="dropdown-subitem"><a href="/note/js-low/" class="nav-link">JavaScript基础笔记</a></li><li class="dropdown-subitem"><a href="/note/js-high/" class="nav-link">JavaScript高阶笔记</a></li><li class="dropdown-subitem"><a href="/note/js-dom-bom/" class="nav-link">JavaScript DOM和BOM笔记</a></li><li class="dropdown-subitem"><a href="/note/jquery/" class="nav-link">jQuery笔记</a></li><li class="dropdown-subitem"><a href="/note/ajax/" class="nav-link">Ajax笔记</a></li><li class="dropdown-subitem"><a href="/note/nodejs/" class="nav-link">NodeJs笔记</a></li><li class="dropdown-subitem"><a href="/note/reg/" class="nav-link">正则表达式笔记</a></li><li class="dropdown-subitem"><a href="/note/vue/" class="nav-link">Vue笔记</a></li><li class="dropdown-subitem"><a href="/note/react/" class="nav-link">react笔记</a></li><li class="dropdown-subitem"><a href="/note/wx/" class="nav-link">微信小程序笔记</a></li><li class="dropdown-subitem"><a href="/note/uniapp/" class="nav-link">uniapp笔记</a></li><li class="dropdown-subitem"><a href="/note/echarts/" class="nav-link">echarts笔记</a></li><li class="dropdown-subitem"><a href="/note/git/" class="nav-link">Git笔记</a></li></ul></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="后端" class="dropdown-title"><a href="/back/" class="link-title">后端</a> <span class="title" style="display:none;">后端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/java/" class="nav-link">JAVA</a></li><li class="dropdown-item"><!----> <a href="/note/javaweb/" class="nav-link">JavaWeb</a></li><li class="dropdown-item"><!----> <a href="/note/mysql/" class="nav-link">MySql</a></li><li class="dropdown-item"><!----> <a href="/note/ssm/" class="nav-link">ssm</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="算法" class="dropdown-title"><a href="/algor/" class="link-title">算法</a> <span class="title" style="display:none;">算法</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/sf/" class="nav-link">算法训练营</a></li><li class="dropdown-item"><!----> <a href="/note/js-sf/" class="nav-link">js数据结构与算法</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="面试" class="dropdown-title"><a href="/mianshi/" class="link-title">面试</a> <span class="title" style="display:none;">面试</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/lqb/" class="nav-link">蓝桥杯备战</a></li><li class="dropdown-item"><!----> <a href="/note/ms/" class="nav-link">前端面试</a></li><li class="dropdown-item"><!----> <a href="/note/hmms/" class="nav-link">黑马面试</a></li><li class="dropdown-item"><!----> <a href="/note/xzms/" class="nav-link">校招零距离面试</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="解决方案" class="dropdown-title"><a href="/resolve/" class="link-title">解决方案</a> <span class="title" style="display:none;">解决方案</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/qd-resolve/" class="nav-link">前端解决方案</a></li><li class="dropdown-item"><!----> <a href="/note/hd-resolve/" class="nav-link">后端解决方案</a></li></ul></div></div><div class="nav-item"><a href="/pages/beb6c0bd8a66cea6/" class="nav-link">收藏</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="索引" class="dropdown-title"><a href="/archives/" class="link-title">索引</a> <span class="title" style="display:none;">索引</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/categories/" class="nav-link">分类</a></li><li class="dropdown-item"><!----> <a href="/tags/" class="nav-link">标签</a></li><li class="dropdown-item"><!----> <a href="/archives/" class="nav-link">归档</a></li></ul></div></div> <a href="https://github.com/linxin1123/vuepress-blog" target="_blank" rel="noopener noreferrer" class="repo-link">
    GitHub
    <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav>  <ul class="sidebar-links"><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>学习笔记</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading open"><span>Java笔记</span> <span class="arrow down"></span></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/pages/ee64d9/" class="sidebar-link">Java复习（一）</a></li><li><a href="/pages/659fa7/" class="sidebar-link">Java复习（二）</a></li><li><a href="/pages/c57687/" class="sidebar-link">Java io流（一）</a></li><li><a href="/pages/8ac044/" class="sidebar-link">Java io流（二）</a></li><li><a href="/pages/2d0d17/" aria-current="page" class="active sidebar-link">Java io流（三）</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level2"><a href="/pages/2d0d17/#_1-学生对象到文件-排序版-使用字符流" class="sidebar-link">1. 学生对象到文件（排序版，使用字符流）</a></li><li class="sidebar-sub-header level2"><a href="/pages/2d0d17/#_2-复制多级文件夹" class="sidebar-link">2. 复制多级文件夹</a></li><li class="sidebar-sub-header level2"><a href="/pages/2d0d17/#_3-io特殊操作流" class="sidebar-link">3. IO特殊操作流</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_3-1-标准输入流" class="sidebar-link">3.1 标准输入流</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#标准输入流转字符流" class="sidebar-link">标准输入流转字符流</a></li><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_3-2-标准输出流" class="sidebar-link">3.2 标准输出流</a></li><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_3-3-字节打印流" class="sidebar-link">3.3 字节打印流</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#字节打印流示例" class="sidebar-link">字节打印流示例</a></li><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_3-4-字符打印流" class="sidebar-link">3.4 字符打印流</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#示例" class="sidebar-link">示例</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#字符打印流复制文件" class="sidebar-link">字符打印流复制文件</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/pages/2d0d17/#_4-对象序列流化" class="sidebar-link">4. 对象序列流化</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#示例-2" class="sidebar-link">示例</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#注意点" class="sidebar-link">注意点</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/pages/2d0d17/#_5-对象反序列化" class="sidebar-link">5. 对象反序列化</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#示例-3" class="sidebar-link">示例</a></li><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_5-1-serialversionuid-和-transient" class="sidebar-link">5.1 serialVersionUID 和 transient</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/pages/2d0d17/#_6-properties-集合的使用" class="sidebar-link">6.Properties 集合的使用</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_6-1-作为map-双列集合-的使用" class="sidebar-link">6.1 作为Map(双列集合)的使用</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#示例-4" class="sidebar-link">示例</a></li><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_6-2-作为map集合的特有方法" class="sidebar-link">6.2 作为Map集合的特有方法</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#示例-5" class="sidebar-link">示例</a></li><li class="sidebar-sub-header level3"><a href="/pages/2d0d17/#_6-3-properties-和-io流相结合的方法" class="sidebar-link">6.3 Properties 和 IO流相结合的方法</a></li><li class="sidebar-sub-header level4"><a href="/pages/2d0d17/#示例-6" class="sidebar-link">示例</a></li></ul></li></ul></li><li><a href="/pages/e16a86/" class="sidebar-link">java-网络编程</a></li><li><a href="/pages/d7d5c4/" class="sidebar-link">Java 反射和注解</a></li></ul></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>JavaWeb笔记</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>MySql笔记</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>SSM笔记</span> <span class="arrow right"></span></p> <!----></section></li></ul> </aside> <div><main class="page"><div class="theme-vdoing-wrapper "><div class="articleInfo-wrap" data-v-06225672><div class="articleInfo" data-v-06225672><ul class="breadcrumbs" data-v-06225672><li data-v-06225672><a href="/" title="首页" class="iconfont icon-home router-link-active" data-v-06225672></a></li> <li data-v-06225672><a href="/back/#后端" data-v-06225672>后端</a></li><li data-v-06225672><a href="/back/#Java笔记" data-v-06225672>Java笔记</a></li></ul> <div class="info" data-v-06225672><div title="作者" class="author iconfont icon-touxiang" data-v-06225672><a href="https://github.com/linxin1123" target="_blank" title="作者" class="beLink" data-v-06225672>lingxin</a></div> <div title="创建时间" class="date iconfont icon-riqi" data-v-06225672><a href="javascript:;" data-v-06225672>2023-01-25</a></div> <!----></div></div></div> <!----> <div class="content-wrapper"><div class="right-menu-wrapper"><div class="right-menu-margin"><div class="right-menu-title">目录</div> <div class="right-menu-content"></div></div></div> <h1><img src="">Java io流（三）<!----></h1>  <div class="theme-vdoing-content content__default"><h1 id="java-io-流-三"><a href="#java-io-流-三" class="header-anchor">#</a> Java IO 流（三）</h1> <p>@<a href="%E7%9B%AE%E5%BD%95">toc</a></p> <h2 id="_1-学生对象到文件-排序版-使用字符流"><a href="#_1-学生对象到文件-排序版-使用字符流" class="header-anchor">#</a> 1. 学生对象到文件（排序版，使用字符流）</h2> <ul><li>学生类</li></ul> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token namespace">third</span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Student</span> <span class="token punctuation">{</span>
    <span class="token keyword">private</span> <span class="token class-name">String</span> name<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> chinese<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> math<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> english<span class="token punctuation">;</span>

    <span class="token keyword">public</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">,</span> <span class="token keyword">int</span> chinese<span class="token punctuation">,</span> <span class="token keyword">int</span> math<span class="token punctuation">,</span> <span class="token keyword">int</span> english<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>chinese <span class="token operator">=</span> chinese<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>math <span class="token operator">=</span> math<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>english <span class="token operator">=</span> english<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token class-name">String</span> <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getChinese</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> chinese<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setChinese</span><span class="token punctuation">(</span><span class="token keyword">int</span> chinese<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>chinese <span class="token operator">=</span> chinese<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getMath</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> math<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setMath</span><span class="token punctuation">(</span><span class="token keyword">int</span> math<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>math <span class="token operator">=</span> math<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getEnglish</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> english<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setEnglish</span><span class="token punctuation">(</span><span class="token keyword">int</span> english<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>english <span class="token operator">=</span> english<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> math<span class="token operator">+</span>english<span class="token operator">+</span>chinese<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br></div></div><ul><li>测试类</li></ul> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token namespace">third</span><span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">BufferedWriter</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">FileWriter</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Comparator</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">TreeSet</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.对集合进行排序</span>
<span class="token comment">//        set集合，treeset的比较器</span>

        <span class="token class-name">TreeSet</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Student</span><span class="token punctuation">&gt;</span></span> ts <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TreeSet</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Student</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Student</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
            <span class="token annotation punctuation">@Override</span>
            <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">compare</span><span class="token punctuation">(</span><span class="token class-name">Student</span> o1<span class="token punctuation">,</span> <span class="token class-name">Student</span> o2<span class="token punctuation">)</span> <span class="token punctuation">{</span>
<span class="token comment">//                1.先比较总分</span>
                <span class="token keyword">int</span> num1<span class="token operator">=</span> o1<span class="token punctuation">.</span><span class="token function">getSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">-</span>o2<span class="token punctuation">.</span><span class="token function">getSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//                2.在比较语文成绩</span>
                <span class="token keyword">int</span> num2<span class="token operator">=</span> num1<span class="token operator">==</span><span class="token number">0</span><span class="token operator">?</span> o1<span class="token punctuation">.</span><span class="token function">getChinese</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">-</span>o2<span class="token punctuation">.</span><span class="token function">getChinese</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">:</span>num1<span class="token punctuation">;</span>
<span class="token comment">//                3.比较数学成绩</span>
                <span class="token keyword">int</span> num3<span class="token operator">=</span> num2<span class="token operator">==</span><span class="token number">0</span><span class="token operator">?</span> o1<span class="token punctuation">.</span><span class="token function">getMath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">-</span>o2<span class="token punctuation">.</span><span class="token function">getMath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">:</span>num2<span class="token punctuation">;</span>
<span class="token comment">//                4.比较英语成绩</span>
                <span class="token keyword">int</span> num4<span class="token operator">=</span> num3<span class="token operator">==</span><span class="token number">0</span><span class="token operator">?</span> o1<span class="token punctuation">.</span><span class="token function">getEnglish</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">-</span>o2<span class="token punctuation">.</span><span class="token function">getEnglish</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">:</span>num3<span class="token punctuation">;</span>
<span class="token comment">//                5.比较姓名</span>
                <span class="token keyword">int</span> num5<span class="token operator">=</span> num4<span class="token operator">==</span><span class="token number">0</span><span class="token operator">?</span> o1<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">compareTo</span><span class="token punctuation">(</span>o2<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">:</span>num4<span class="token punctuation">;</span>

                <span class="token keyword">return</span> <span class="token operator">-</span>num5<span class="token punctuation">;</span>
            <span class="token punctuation">}</span>
        <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        创建学生对象</span>
        <span class="token class-name">Student</span> s1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;heima001&quot;</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">90</span><span class="token punctuation">,</span><span class="token number">80</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">Student</span> s2 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;heima002&quot;</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">80</span><span class="token punctuation">,</span><span class="token number">90</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">Student</span> s3 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;heima003&quot;</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">90</span><span class="token punctuation">,</span><span class="token number">80</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">Student</span> s4 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;heima004&quot;</span><span class="token punctuation">,</span><span class="token number">90</span><span class="token punctuation">,</span><span class="token number">90</span><span class="token punctuation">,</span><span class="token number">90</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        添加对象到set集合</span>
        ts<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ts<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s2<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ts<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s3<span class="token punctuation">)</span><span class="token punctuation">;</span>
        ts<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>s4<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        把对象写入文件</span>

        <span class="token class-name">BufferedWriter</span> bw <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">BufferedWriter</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">FileWriter</span><span class="token punctuation">(</span><span class="token string">&quot;code\\8.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">Student</span> s<span class="token operator">:</span>ts<span class="token punctuation">)</span><span class="token punctuation">{</span>
<span class="token comment">//            新建一个可变字符串</span>
            <span class="token class-name">StringBuilder</span> sb <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">StringBuilder</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            sb<span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span><span class="token string">&quot;,&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getChinese</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span><span class="token string">&quot;,&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getMath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span><span class="token string">&quot;,&quot;</span><span class="token punctuation">)</span>
                    <span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getEnglish</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span><span class="token string">&quot;,&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            bw<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>sb<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            bw<span class="token punctuation">.</span><span class="token function">newLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
            bw<span class="token punctuation">.</span><span class="token function">flush</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

        bw<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br><span class="line-number">58</span><br><span class="line-number">59</span><br><span class="line-number">60</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/80bb484e55d24c309f969d3c6279a766.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <h2 id="_2-复制多级文件夹"><a href="#_2-复制多级文件夹" class="header-anchor">#</a> 2. 复制多级文件夹</h2> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 复制单级目录<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        源目录对象</span>
        <span class="token class-name">File</span> srcFile<span class="token operator">=</span><span class="token keyword">new</span> <span class="token class-name">File</span><span class="token punctuation">(</span><span class="token string">&quot;E:\\file&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        获取单个目录对象的名称（file）</span>
        <span class="token class-name">String</span> srcFoldFile<span class="token operator">=</span>srcFile<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        复制到哪里</span>
        <span class="token class-name">File</span> destFile <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">File</span><span class="token punctuation">(</span><span class="token string">&quot;E:\\myfile&quot;</span><span class="token punctuation">,</span>srcFoldFile<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        判断目录是否存在</span>

        <span class="token keyword">if</span><span class="token punctuation">(</span><span class="token operator">!</span>destFile<span class="token punctuation">.</span><span class="token function">exists</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
<span class="token comment">//            没有则创建目录</span>
            destFile<span class="token punctuation">.</span><span class="token function">mkdirs</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

<span class="token comment">//        获取源目录下的文件对象</span>

        <span class="token class-name">File</span><span class="token punctuation">[</span><span class="token punctuation">]</span> files <span class="token operator">=</span> srcFile<span class="token punctuation">.</span><span class="token function">listFiles</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        对于每个对象，如果是文件，直接复制，如果是目录，递归调用</span>

<span class="token comment">//        for(File s:files){</span>
<span class="token comment">//            System.out.println(s);</span>
<span class="token comment">//        }</span>
        <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">File</span> f<span class="token operator">:</span>files<span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token function">fileSearch</span><span class="token punctuation">(</span>f<span class="token punctuation">,</span>destFile<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">copy</span><span class="token punctuation">(</span><span class="token class-name">File</span> srcFile<span class="token punctuation">,</span><span class="token class-name">File</span> destFile<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
        <span class="token class-name">FileOutputStream</span> fos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileOutputStream</span><span class="token punctuation">(</span>destFile<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">FileInputStream</span> fis <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileInputStream</span><span class="token punctuation">(</span>srcFile<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">int</span> len<span class="token punctuation">;</span>
        <span class="token keyword">byte</span><span class="token punctuation">[</span><span class="token punctuation">]</span>bys<span class="token operator">=</span><span class="token keyword">new</span> <span class="token keyword">byte</span><span class="token punctuation">[</span><span class="token number">1024</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
        <span class="token keyword">while</span><span class="token punctuation">(</span><span class="token punctuation">(</span>len<span class="token operator">=</span>fis<span class="token punctuation">.</span><span class="token function">read</span><span class="token punctuation">(</span>bys<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">!=</span><span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            fos<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>bys<span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span>len<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">fileSearch</span><span class="token punctuation">(</span><span class="token class-name">File</span> f<span class="token punctuation">,</span><span class="token class-name">File</span> destFile<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
        <span class="token class-name">File</span> dFile<span class="token operator">=</span><span class="token keyword">new</span> <span class="token class-name">File</span><span class="token punctuation">(</span>destFile<span class="token punctuation">,</span>f<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">if</span><span class="token punctuation">(</span>f<span class="token punctuation">.</span><span class="token function">isFile</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
<span class="token comment">//            是文件，直接复制</span>
            <span class="token function">copy</span><span class="token punctuation">(</span>f<span class="token punctuation">,</span>dFile<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span><span class="token keyword">else</span> <span class="token keyword">if</span><span class="token punctuation">(</span>f<span class="token punctuation">.</span><span class="token function">isDirectory</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
<span class="token comment">//            不是文件，创建目录</span>
            dFile<span class="token punctuation">.</span><span class="token function">mkdir</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//            递归目录里面的文件</span>
            <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">File</span> f3<span class="token operator">:</span>f<span class="token punctuation">.</span><span class="token function">listFiles</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
                <span class="token function">fileSearch</span><span class="token punctuation">(</span>f3<span class="token punctuation">,</span> dFile<span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token punctuation">}</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br><span class="line-number">58</span><br><span class="line-number">59</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/2573752b034945b7b20472e443814715.gif#pic_center" alt="在这里插入图片描述"></p> <h2 id="_3-io特殊操作流"><a href="#_3-io特殊操作流" class="header-anchor">#</a> 3. IO特殊操作流</h2> <h3 id="_3-1-标准输入流"><a href="#_3-1-标准输入流" class="header-anchor">#</a> 3.1 标准输入流</h3> <ul><li>System类的两个静态的成员变量
<ul><li><strong>public static final InputStream in:标准输入流，通常该流对应键盘输入或用户定义或主机环境指定的输入</strong></li> <li><strong>public static final PrintStream out,标准输出流，通常该流对应显示输出或由主机环境和用户指定</strong></li></ul></li></ul> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 标准输入流<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">InputStream</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo1</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.定义一个标准输入流变量</span>
<span class="token comment">//        数据来源键盘输入</span>
        <span class="token class-name">InputStream</span> is<span class="token operator">=</span><span class="token class-name">System</span><span class="token punctuation">.</span>in<span class="token punctuation">;</span>

        <span class="token keyword">int</span> len<span class="token punctuation">;</span>
        <span class="token keyword">while</span><span class="token punctuation">(</span><span class="token punctuation">(</span>len<span class="token operator">=</span>is<span class="token punctuation">.</span><span class="token function">read</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">!=</span><span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token keyword">char</span><span class="token punctuation">)</span>len<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/562e335c4a4e4373942f55a3371755e3.gif#pic_center" alt="在这里插入图片描述"></p> <h4 id="标准输入流转字符流"><a href="#标准输入流转字符流" class="header-anchor">#</a> 标准输入流转字符流</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 标准输入流<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">BufferedReader</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">InputStream</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">InputStreamReader</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo1</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.定义一个标准输入流变量</span>
<span class="token comment">//        数据来源键盘输入</span>
        <span class="token class-name">InputStream</span> is<span class="token operator">=</span><span class="token class-name">System</span><span class="token punctuation">.</span>in<span class="token punctuation">;</span>

<span class="token comment">//        int len;</span>
<span class="token comment">//        while((len=is.read())!=-1){</span>
<span class="token comment">//            System.out.println((char)len);</span>
<span class="token comment">//        }</span>

<span class="token comment">//        字节流到字符流的转换</span>
        <span class="token class-name">InputStreamReader</span> isr <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">InputStreamReader</span><span class="token punctuation">(</span>is<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        字符流到字符缓冲流，实现一次读取一行数据</span>

        <span class="token class-name">BufferedReader</span> br <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">BufferedReader</span><span class="token punctuation">(</span>isr<span class="token punctuation">)</span><span class="token punctuation">;</span>

       <span class="token class-name">String</span> str<span class="token punctuation">;</span>
        <span class="token keyword">while</span><span class="token punctuation">(</span><span class="token punctuation">(</span>str<span class="token operator">=</span>br<span class="token punctuation">.</span><span class="token function">readLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">!=</span><span class="token keyword">null</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>str<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

        isr<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        br<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>



    <span class="token punctuation">}</span>


<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/eef96224fb154eb1a5a5370bdc5bee19.gif#pic_center" alt="在这里插入图片描述"></p> <h3 id="_3-2-标准输出流"><a href="#_3-2-标准输出流" class="header-anchor">#</a> 3.2 标准输出流</h3> <ul><li><strong>public static final PrintStream out</strong></li></ul> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 标准输入流<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">PrintStream</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo2</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token comment">//    1.创建标准输出流</span>

        <span class="token class-name">PrintStream</span> ps<span class="token operator">=</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">;</span>

        ps<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">&quot;666&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        等价于</span>

        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">&quot;666&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/53e4c755096e4ebba0983318323e9255.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <h3 id="_3-3-字节打印流"><a href="#_3-3-字节打印流" class="header-anchor">#</a> 3.3 字节打印流</h3> <ul><li><p><strong>字节打印流：PrintStream</strong></p></li> <li><p><strong>字符打印流：PrintWriter</strong></p></li> <li><p>打印流的特点</p> <ul><li><strong>只负责输出，只写数据</strong></li> <li><strong>写数据有特有方法：print，println</strong></li></ul></li></ul> <h4 id="字节打印流示例"><a href="#字节打印流示例" class="header-anchor">#</a> 字节打印流示例</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 字节打印流<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">FileNotFoundException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">PrintStream</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo1</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.创建字节打印流对象</span>

        <span class="token class-name">PrintStream</span> ps <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PrintStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\9.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        1.标准写法，其他字节流也有的方法</span>
<span class="token comment">//        打印的是acall码对应的字符</span>
        ps<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token number">97</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">String</span> str<span class="token operator">=</span><span class="token string">&quot;2222\r\n&quot;</span><span class="token punctuation">;</span>
        ps<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>str<span class="token punctuation">.</span><span class="token function">getBytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        2.特有方法，打什么是什么</span>
        ps<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token number">111</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        ps<span class="token punctuation">.</span><span class="token function">print</span><span class="token punctuation">(</span><span class="token number">99</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        ps<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/ab3cb47fdc6a4d6aaca415c4396b4941.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <h3 id="_3-4-字符打印流"><a href="#_3-4-字符打印流" class="header-anchor">#</a> 3.4 字符打印流</h3> <ul><li><strong>构造方法（这些方法可以在jdk文档中查看，学习时多看这些文档）</strong></li></ul> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>PrintWriter(String fileName)</td> <td>根据文件名创建pw，不执行自动flush</td></tr> <tr><td>PrintWriter(String fileName,boolean autoFlush)</td> <td>第二个参数代表是否自动刷新</td></tr></tbody></table> <h4 id="示例"><a href="#示例" class="header-anchor">#</a> 示例</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 字节打印流<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">FileNotFoundException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">FileWriter</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">PrintWriter</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo2</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
        <span class="token class-name">PrintWriter</span> pw <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PrintWriter</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">FileWriter</span><span class="token punctuation">(</span><span class="token string">&quot;code\\10.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pw<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token number">1111</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pw<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token number">111</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pw<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token number">97</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        pw<span class="token punctuation">.</span><span class="token function">flush</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        pw<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/9a8e9c745b774848a9c03cf4b5fb36f7.png#pic_center" alt="在这里插入图片描述"></p> <h4 id="字符打印流复制文件"><a href="#字符打印流复制文件" class="header-anchor">#</a> 字符打印流复制文件</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 字节打印流<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo3</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.使用字符打印流复制文件</span>

<span class="token comment">//        创建字符打印流</span>
        <span class="token class-name">PrintWriter</span> pw <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PrintWriter</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">FileWriter</span><span class="token punctuation">(</span><span class="token string">&quot;code\\11.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        创建字符缓冲流</span>

        <span class="token class-name">BufferedReader</span> br <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">BufferedReader</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">FileReader</span><span class="token punctuation">(</span><span class="token string">&quot;code\\9.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">String</span> len<span class="token punctuation">;</span>

        <span class="token keyword">while</span><span class="token punctuation">(</span><span class="token punctuation">(</span>len<span class="token operator">=</span>br<span class="token punctuation">.</span><span class="token function">readLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">!=</span><span class="token keyword">null</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
            pw<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>len<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>

        br<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pw<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/e43551664f53494abacc2ec6db2e9a5c.gif#pic_center" alt="在这里插入图片描述"></p> <h2 id="_4-对象序列流化"><a href="#_4-对象序列流化" class="header-anchor">#</a> 4. 对象序列流化</h2> <ul><li><p><strong>对象序列化：将对象保存在磁盘中，或在网络中传输对象</strong></p></li> <li><p><strong>一个字节序列表示一个对象，该字节序列包括：对象的类型，对象的数据，对象的属性等信息</strong></p></li> <li><p>构造方法</p></li></ul> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>ObjectOutputStream</td> <td>创建一个写入指定的Output Stream的oos</td></tr></tbody></table> <ul><li><strong>序列化对象的方法</strong></li></ul> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>void writeObject(Object obj)</td> <td>将指定对象写入oos</td></tr></tbody></table> <h4 id="示例-2"><a href="#示例-2" class="header-anchor">#</a> 示例</h4> <ul><li>学生类</li></ul> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 对象序列化<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">Serializable</span></span><span class="token punctuation">;</span>

<span class="token comment">//   对象序列化，前提需要这个类实现了Ser.....接口</span>
<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Student</span> <span class="token keyword">implements</span> <span class="token class-name">Serializable</span> <span class="token punctuation">{</span>
    <span class="token keyword">private</span> <span class="token class-name">String</span> name<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> chinese<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> math<span class="token punctuation">;</span>
    <span class="token keyword">private</span> <span class="token keyword">int</span> english<span class="token punctuation">;</span>

    <span class="token keyword">public</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">,</span> <span class="token keyword">int</span> chinese<span class="token punctuation">,</span> <span class="token keyword">int</span> math<span class="token punctuation">,</span> <span class="token keyword">int</span> english<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>chinese <span class="token operator">=</span> chinese<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>math <span class="token operator">=</span> math<span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>english <span class="token operator">=</span> english<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token class-name">String</span> <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getChinese</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> chinese<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setChinese</span><span class="token punctuation">(</span><span class="token keyword">int</span> chinese<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>chinese <span class="token operator">=</span> chinese<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getMath</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> math<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setMath</span><span class="token punctuation">(</span><span class="token keyword">int</span> math<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>math <span class="token operator">=</span> math<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getEnglish</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> english<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setEnglish</span><span class="token punctuation">(</span><span class="token keyword">int</span> english<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>english <span class="token operator">=</span> english<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getSum</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> math<span class="token operator">+</span>english<span class="token operator">+</span>chinese<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br></div></div><ul><li>测试类</li></ul> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 对象序列化<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">FileOutputStream</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">IOException</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">ObjectOutputStream</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token class-name">OutputStream</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.创建序列化oos对象</span>
        <span class="token class-name">FileOutputStream</span> fos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileOutputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\12.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">ObjectOutputStream</span> oos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ObjectOutputStream</span><span class="token punctuation">(</span>fos<span class="token punctuation">)</span><span class="token punctuation">;</span>


<span class="token comment">//        2.创建一个学生对象</span>

        <span class="token class-name">Student</span> s1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;bob&quot;</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        3.对象序列化写入文件</span>

        oos<span class="token punctuation">.</span><span class="token function">writeObject</span><span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">;</span>

        oos<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/cdd4d4b24aed408abdf8ee9e134ed62f.png#pic_center" alt="在这里插入图片描述"></p> <h4 id="注意点"><a href="#注意点" class="header-anchor">#</a> 注意点</h4> <ul><li><strong>要序列化的对象需要实现Serializable接口</strong></li> <li><strong>实现该接口不需要重写任何方法</strong></li></ul> <h2 id="_5-对象反序列化"><a href="#_5-对象反序列化" class="header-anchor">#</a> 5. 对象反序列化</h2> <ul><li>构造方法</li></ul> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>ObjectInputStream(InputStream in)</td> <td>创建从InputStream读取的ois</td></tr></tbody></table> <ul><li>读取方法</li></ul> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>Object readObject()</td> <td>从ois读取一个对象，返回值object类型</td></tr></tbody></table> <h4 id="示例-3"><a href="#示例-3" class="header-anchor">#</a> 示例</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 对象序列化<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span><span class="token punctuation">,</span> <span class="token class-name">ClassNotFoundException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.创建序列化oos对象</span>
        <span class="token class-name">FileOutputStream</span> fos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileOutputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\12.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">ObjectOutputStream</span> oos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ObjectOutputStream</span><span class="token punctuation">(</span>fos<span class="token punctuation">)</span><span class="token punctuation">;</span>


<span class="token comment">//        2.创建一个学生对象</span>

        <span class="token class-name">Student</span> s1 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;bob&quot;</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        3.对象序列化写入文件</span>

        oos<span class="token punctuation">.</span><span class="token function">writeObject</span><span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        4.反序列化对象</span>
        <span class="token class-name">FileInputStream</span> fis <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileInputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\12.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">ObjectInputStream</span> ois <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ObjectInputStream</span><span class="token punctuation">(</span>fis<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        读取数据</span>

        <span class="token class-name">Student</span> s<span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Student</span><span class="token punctuation">)</span> ois<span class="token punctuation">.</span><span class="token function">readObject</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">getMath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        oos<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/56b62ccdf6df4c839afbcafb99c18fd8.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <h3 id="_5-1-serialversionuid-和-transient"><a href="#_5-1-serialversionuid-和-transient" class="header-anchor">#</a> 5.1 serialVersionUID 和 transient</h3> <ul><li><p>用对象序列化一个对象后，<strong>假如我们修改了对象所属的类（类中的内容发生了改变），读取数据会出问题</strong></p> <ol><li><strong>抛出InvaildClassException异常</strong></li></ol></li> <li><p>解决</p> <ul><li>重新序列化</li> <li><strong>给对象所属的类加一个serialVersionUID(常量，不在变化)</strong></li></ul></li> <li><p>如果<strong>一个对象的某个成员变量不想被序列化</strong>，给该变量添加<strong>transient关键字修饰</strong></p></li></ul> <blockquote><ul><li>序列化运行时与每个可序列化的类关联一个版本号，称为serialVersionUID，它在反序列化过程中使用，以验证序列化对象的发送者和接收者是否加载了与序列化兼容的对象的类。  如果接收者已经为具有与对应发件人类别不同的serialVersionUID的对象加载了一个类，则反序列化将导致一个<a href="/java/io/InvalidClassException.html"><code>InvalidClassException</code></a>  。  一个可序列化的类可以通过声明一个名为<code>&quot;serialVersionUID&quot;</code>的字段来显式地声明它自己的serialVersionUID，该字段必须是static，final和<code>long</code>类型：</li></ul> <div class="language- line-numbers-mode"><pre class="language-text"><code>  ANY-ACCESS-MODIFIER static final long serialVersionUID = 42L; 
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><p>如果可序列化类没有显式声明serialVersionUID，则序列化运行时将根据Java（TM）对象序列化规范中所述的类的各个方面计算该类的默认serialVersionUID值。然而，  <em>强烈建议</em>所有可序列化的类显式声明serialVersionUID值，因为默认的serialVersionUID计算对类细节非常敏感，这些细节可能因编译器实现而异，因此可能会在反序列化期间导致意外的<code>InvalidClassException</code>  。因此，为了保证不同Java编译器实现之间的一致的serialVersionUID值，一个可序列化的类必须声明一个显式的serialVersionUID值。还强烈建议，显式的serialVersionUID声明在可能的情况下使用<code>private</code>修饰符，因为这种声明仅适用于立即声明的类  - serialVersionUID字段作为继承成员无效。</p></blockquote> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> 对象序列化<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo2</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span><span class="token punctuation">,</span> <span class="token class-name">ClassNotFoundException</span> <span class="token punctuation">{</span>
        <span class="token class-name">FileOutputStream</span> fos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileOutputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\12.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">FileInputStream</span> fis <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileInputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\12.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        对象序列化</span>

        <span class="token class-name">ObjectOutputStream</span> oos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ObjectOutputStream</span><span class="token punctuation">(</span>fos<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">Student</span> s<span class="token operator">=</span><span class="token keyword">new</span> <span class="token class-name">Student</span><span class="token punctuation">(</span><span class="token string">&quot;judy&quot;</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        oos<span class="token punctuation">.</span><span class="token function">writeObject</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">ObjectInputStream</span> ois <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ObjectInputStream</span><span class="token punctuation">(</span>fis<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//      反序列化</span>

        <span class="token class-name">Object</span> o <span class="token operator">=</span> ois<span class="token punctuation">.</span><span class="token function">readObject</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">Student</span> s2<span class="token operator">=</span><span class="token punctuation">(</span><span class="token class-name">Student</span><span class="token punctuation">)</span> o<span class="token punctuation">;</span>
<span class="token comment">//        second.Student s3=(second.Student) o;</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s2<span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        System.out.println(s3.getName());</span>

    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/6eedd200e5de4319a7310f0ec72286f1.png#pic_center" alt="在这里插入图片描述"></p> <ul><li>uid使用与否对比图</li></ul> <p><img src="https://img-blog.csdnimg.cn/20913ef222ef4c42afd2b65ef62a977f.gif#pic_center" alt="在这里插入图片描述"></p> <p><img src="https://img-blog.csdnimg.cn/11a54b2e25ad41bab4dd879133f70378.gif#pic_center" alt="在这里插入图片描述"></p> <h2 id="_6-properties-集合的使用"><a href="#_6-properties-集合的使用" class="header-anchor">#</a> 6.Properties 集合的使用</h2> <h3 id="_6-1-作为map-双列集合-的使用"><a href="#_6-1-作为map-双列集合-的使用" class="header-anchor">#</a> 6.1 作为Map(双列集合)的使用</h3> <ul><li>简介
<ul><li><strong>是一个Map体系的集合类</strong></li> <li><strong>Properties可以保存到流或从流中加载</strong></li> <li><strong>键和值都是字符串</strong></li></ul></li></ul> <h4 id="示例-4"><a href="#示例-4" class="header-anchor">#</a> 示例</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token class-name">Properties</span>集合的使用<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Properties</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Set</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> demo <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token class-name">Properties</span> pt <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Properties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        pt<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">&quot;bob&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;15&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">&quot;judy&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;19&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">&quot;kate&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;25&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        和Map集合一样的操作方法</span>

        <span class="token class-name">Set</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Object</span><span class="token punctuation">&gt;</span></span> sets <span class="token operator">=</span> pt<span class="token punctuation">.</span><span class="token function">keySet</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">Object</span> o<span class="token operator">:</span>sets<span class="token punctuation">)</span><span class="token punctuation">{</span>
<span class="token comment">//            获取值</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>o<span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>pt<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>o<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token punctuation">}</span>

    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/cf8d5ee85cf1485e8bd717724778edfc.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <h3 id="_6-2-作为map集合的特有方法"><a href="#_6-2-作为map集合的特有方法" class="header-anchor">#</a> 6.2 作为Map集合的特有方法</h3> <ul><li>特有方法</li></ul> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>Object setProperty(String key,String value)</td> <td>设置集合的键和值,底层调用Hash Map的put方法</td></tr> <tr><td>String getProperty(String key)</td> <td>根据键搜索值</td></tr> <tr><td>Set stringPropeytyNames()</td> <td>返回一个键的集合,键与值都是字符串</td></tr></tbody></table> <h4 id="示例-5"><a href="#示例-5" class="header-anchor">#</a> 示例</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token class-name">Properties</span>集合的使用<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Properties</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Set</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> demo2 <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token class-name">Properties</span> pt <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Properties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        1.设置集合的键与值</span>
        pt<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">&quot;bob&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;13&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">&quot;kob&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;13&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">&quot;lob&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;13&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        2.根据键获取值</span>
        pt<span class="token punctuation">.</span><span class="token function">getProperty</span><span class="token punctuation">(</span><span class="token string">&quot;bob&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        3.获取键的集合</span>
        <span class="token class-name">Set</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> strings <span class="token operator">=</span> pt<span class="token punctuation">.</span><span class="token function">stringPropertyNames</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">String</span> s<span class="token operator">:</span>strings<span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>pt<span class="token punctuation">.</span><span class="token function">getProperty</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>


    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/d390d0324f24482b8dc5be38bb2d3125.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p> <h3 id="_6-3-properties-和-io流相结合的方法"><a href="#_6-3-properties-和-io流相结合的方法" class="header-anchor">#</a> 6.3 Properties 和 IO流相结合的方法</h3> <ul><li><p>与IO流相结合</p> <table><thead><tr><th>方法名</th> <th>说明</th></tr></thead> <tbody><tr><td>void load(InputStream inStream)</td> <td>从输入字节流读取属性列表(键值对)</td></tr> <tr><td>void load(Reader reader)</td> <td>从输入字符流读取属性列表</td></tr> <tr><td>void store(OutputStream,String comments)</td> <td>写入输出字节流</td></tr> <tr><td>void store(Writer writer,String comments)</td> <td>写入输出字符流</td></tr></tbody></table></li></ul> <h4 id="示例-6"><a href="#示例-6" class="header-anchor">#</a> 示例</h4> <div class="language-java line-numbers-mode"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token class-name">Properties</span>集合的使用<span class="token punctuation">;</span>

<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>io<span class="token punctuation">.</span></span><span class="token operator">*</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Properties</span></span><span class="token punctuation">;</span>
<span class="token keyword">import</span> <span class="token import"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span><span class="token class-name">Set</span></span><span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Demo3</span> <span class="token punctuation">{</span>
    <span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{</span>
<span class="token comment">//        1.创建字节输入流</span>
        <span class="token class-name">FileInputStream</span> fis <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileInputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\13.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        2.创建字节输出流</span>
        <span class="token class-name">FileOutputStream</span> fos <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileOutputStream</span><span class="token punctuation">(</span><span class="token string">&quot;code\\13.txt&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">//        3.创建字符输入流</span>
<span class="token comment">//        FileReader fr = new FileReader(&quot;code\\13.txt&quot;);</span>
<span class="token comment">//        FileWriter fw = new FileWriter(&quot;code\\13.txt&quot;);</span>

        <span class="token class-name">Properties</span> pt <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Properties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">&quot;bob&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;13&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">&quot;judy&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;13&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">&quot;kate&quot;</span><span class="token punctuation">,</span><span class="token string">&quot;13&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

        pt<span class="token punctuation">.</span><span class="token function">store</span><span class="token punctuation">(</span>fos<span class="token punctuation">,</span><span class="token keyword">null</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">Properties</span> pt2<span class="token operator">=</span><span class="token keyword">new</span> <span class="token class-name">Properties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        pt2<span class="token punctuation">.</span><span class="token function">load</span><span class="token punctuation">(</span>fis<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//        获取键</span>
        <span class="token class-name">Set</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">&gt;</span></span> keys <span class="token operator">=</span> pt2<span class="token punctuation">.</span><span class="token function">stringPropertyNames</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">String</span> s<span class="token operator">:</span>keys<span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s<span class="token operator">+</span><span class="token string">&quot;,&quot;</span><span class="token operator">+</span>pt2<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span>


    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img-blog.csdnimg.cn/03baf4a6f64b46a780d65d7c07bc1784.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5YeM5q2G,size_20,color_FFFFFF,t_70,g_se,x_16#pic_center" alt="在这里插入图片描述"></p></div></div>  <div class="page-edit"><div class="edit-link"><a href="https://github.com/linxin1123/vuepress-blog/edit/master/docs/02.后端/41.Java笔记/05.Java io流（三）.md" target="_blank" rel="noopener noreferrer">编辑</a> <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></div> <!----> <div class="last-updated"><span class="prefix">上次更新:</span> <span class="time">2023/02/17, 11:29:32</span></div></div> <div class="page-nav-wapper"><div class="page-nav-centre-wrap"><a href="/pages/8ac044/" class="page-nav-centre page-nav-centre-prev"><div class="tooltip">Java io流（二）</div></a> <a href="/pages/e16a86/" class="page-nav-centre page-nav-centre-next"><div class="tooltip">java-网络编程</div></a></div> <div class="page-nav"><p class="inner"><span class="prev">
        ←
        <a href="/pages/8ac044/" class="prev">Java io流（二）</a></span> <span class="next"><a href="/pages/e16a86/">java-网络编程</a>→
      </span></p></div></div></div> <div class="article-list"><div class="article-title"><a href="/archives/" class="iconfont icon-bi">最近更新</a></div> <div class="article-wrapper"><dl><dd>01</dd> <dt><a href="/pages/0b785d/"><div>
            Vuex
            <!----></div></a> <span class="date">03-14</span></dt></dl><dl><dd>02</dd> <dt><a href="/pages/c59cc0/"><div>
            Vue响应式原理
            <!----></div></a> <span class="date">03-14</span></dt></dl><dl><dd>03</dd> <dt><a href="/pages/83cc7a/"><div>
            Vue虚拟DOM-cnblog
            <!----></div></a> <span class="date">03-14</span></dt></dl> <dl><dd></dd> <dt><a href="/archives/" class="more">更多文章&gt;</a></dt></dl></div></div></main></div> <div class="footer"><div class="icons"><a href="3010733382@qq.com" title="发邮件" target="_blank" class="iconfont icon-youjian"></a><a href="https://github.com/linxin1123" title="GitHub" target="_blank" class="iconfont icon-github"></a><a href="https://music.163.com/#/playlist?id=755597173" title="听音乐" target="_blank" class="iconfont icon-erji"></a></div> 
  Theme by
  <a href="https://github.com/xugaoyi/vuepress-theme-vdoing" target="_blank" title="本站主题">Vdoing</a> 
    | Copyright © 2022-2023
    <span>lingxin | <a href="https://github.com/linxin1123/vuepress-blog/blob/master/LICENSE" target="_blank">MIT License</a></span></div> <div class="buttons"><div title="返回顶部" class="button blur go-to-top iconfont icon-fanhuidingbu" style="display:none;"></div> <div title="去评论" class="button blur go-to-comment iconfont icon-pinglun" style="display:none;"></div> <div title="主题模式" class="button blur theme-mode-but iconfont icon-zhuti"><ul class="select-box" style="display:none;"><li class="iconfont icon-zidong">
          跟随系统
        </li><li class="iconfont icon-rijianmoshi">
          浅色模式
        </li><li class="iconfont icon-yejianmoshi">
          深色模式
        </li><li class="iconfont icon-yuedu">
          阅读模式
        </li></ul></div></div> <!----> <!----> <!----></div><div class="global-ui"><div></div></div></div>
    <script src="/assets/js/app.57550e13.js" defer></script><script src="/assets/js/2.f014c35f.js" defer></script><script src="/assets/js/87.e06ee05e.js" defer></script>
  </body>
</html>
